genus Otaria vs mammal genus

genus Otaria and mammal genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Otaria	Yes	No	No	No
mammal genus	Yes	No	No	No

As nouns, mammal genus is a hypernym of genus Otaria; that is, mammal genus is a word with a broader meaning than genus Otaria:

genus Otaria (noun)	mammal genus (noun)
type genus of the Otariidae	a genus of mammals